The new findings come from a small Imperial College London and DnaNudge pilot study involving 148 people with high blood sugar levels who were at risk of going on to develop type 2 diabetes.
The findings revealed that following personalised dietary advice informed by genetic information, in combination with face-to-face dietary coaching from a healthcare professional, was more effective at reducing blood glucose levels than standard dietary coaching based on the NICE guidelines, which are the current standard of care in the UK.
While the work is at an early stage, the researchers say it is a promising example of how genetic data might help to prevent long-term conditions and improve health.
Larger trials are needed to verify their findings and to ensure the approach is suitable for use in clinical practice and for a range of people and conditions.
According to the researchers, “genetic profiles of chronic conditions, such as type 2 diabetes, obesity, hypertension, and blood cholesterol can tell us which foods for individuals might be better or worse at reducing the risk of these conditions, allowing us to specifically tailor advice around their dietary intake of fats, carbohydrates, and other macronutrients”.
This pilot study was able to apply this to pre-diabetes and showed promising results, suggesting that genetically-informed diets could be an effective intervention compared to, or combined with, standard advice.
About pre-diabetes, type 2 diabetes
Pre-diabetes is a term used to classify when a person’s blood glucose is consistently higher than usual, but not yet high enough to be classed as type 2 diabetes. Unlike diabetes, pre-diabetes is reversible, but if left unaddressed, up to 10 per cent of people with pre-diabetes progress to T2D each year.
Diabetes is a major cause of sight loss, kidney failure, heart attacks, stroke and lower limb amputation. Ninety per cent of people who have diabetes have type 2 diabetes.
Lifestyle changes – improved diet and increased physical activity – can reduce the likelihood of pre-diabetes progressing to type 2 diabetes by one-half.
Certain genetic traits can predict a person’s risk of developing diet-related chronic conditions, underlining the importance of dietary modifications, such as changing salt, fat and saturated fat to address cardiovascular risk or changing sugar and saturated fat intake for type 2 diabetes risk.
The DnaNudge study
Based on this, Imperial spinout DnaNudge developed the framework for providing personalised diet plans based on people’s genetic profiles, which could be obtained from a sample of saliva.
To test the effects of DNA-based diets on pre-diabetes, the researchers recruited 148 people with high blood sugar levels and took baseline measurements of fasting plasma glucose (levels of sugar in the blood between meals) as well as hemoglobin A1c levels. A hemoglobin A1c (HbA1c) test measures your average blood sugar level over the past three months. It’s used to diagnose prediabetes and diabetes, as well as help guide diabetes management.
Participants also completed a questionnaire outlining how often they consumed certain foods.
Participants were assigned to one of three groups: 1) the control group, who received standard dietary advice from a dietitian only; 2) the intervention group, who received coaching and a DNA-based diet; and 3) the exploratory group, who received no coaching but were self-guided by DnaNudge’s app and wearable device that enabled them to scan barcodes and receive DNA-personalised food and drink recommendations while shopping.
They tested participants’ fasting glucose and hemoglobin A1C again at six, 12 and 26 weeks.
DNA-based diet more effective at reducing glucose
They found no statistically significant difference between the groups at six weeks, but a significant reduction in both glucose measures among participants using the DNA-based diet, both with and without the DnaNudge app, compared to the control group at 26 weeks.
The lead study author said, “prior to progression to type 2 diabetes, people and their healthcare professionals have an opportunity to reduce their risk. The NICE (standard) guidance for lifestyle change – e.g., the inclusion of fruits, vegetables, healthy fats and whole grains – are evidence based and effective for a population, but our findings suggest that personalisation by genetically tailoring dietary advice to an individual might have an even greater effect.”
The researchers said their results should be treated with caution because of the study’s small size of 148, and that the results warrant confirmation in a larger randomised controlled trial.
They also noted that any genetic risk factors for type 2 diabetes could have limited effects when compared with other biological or socioeconomic vulnerabilities, as well as inequalities in access to healthcare, associated with race and ethnicity.
The research team intends to run a larger, multi-national trial with thousands of participants to validate the results. The larger sample size will also allow them to include results within diverse ethnic groups and genders, which can affect the likelihood of developing type 2 diabetes.
Source: Nature Scientific Reports, March 5, 2024.
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